13 Crazy Things That Happen to Your Body During Sex

While you’re caught up in the heat of the moment with your beau, your body is busy getting seriously… creative. A whole host of crazy things happen within your body when you’re having sex. Sex researchers (yes that’s a job) have been enlightening us with insights for years ––and today we’ll share a few with you. 

Let’s go beyond your average sex facts like heavy breathing, or increased heart rate. Here are 13 crazy things you never knew happened to your body during sex. 

#1 Your brain gets high on its own supply

Like, seriously. A sex-driven flood of feel-good neurochemicals sweeps in to induce feelings of euphoria, bliss, and reward. 

Right before orgasm, your hypothalamus goes into “superpower mode” and prepares you for the feel-good chemical cocktail you're about to enjoy. During sex, your brain is flooded by oxytocin (the love hormone) and dopamine (the pleasure chemical). 

Then a balancing act ensues and the influx of oxytocin lowers circulating stress hormones.

It’s no wonder we feel so good after sex. Our brains love it. 

#2 Breasts become 25% bigger

The girls get a little boost when you’re aroused. They can actually become 25% bigger, temporarily. This is thought to be due to increased blood circulation caused by arousal. Your lady and fella bits engorge with blood during arousal, and so too do breasts. Because of this, breasts can become very sensitive to stimulation ––an added bonus.  

#3 The vagina can deepen by 200%

An average vaginal canal is only around 3 - 4 inches deep at any given time. But when aroused, the body quite literally “makes room” for penetration. 

During sex, the cervix and uterus are pulled higher up into the body which can lengthen the vagina to 5 to 8 inches deep. (Length can be determined by the level of arousal.) 

This is called vaginal “tenting”. Crazy, huh? 

#4 But, just before orgasm, the vagina contracts and creates suction

The vaginal walls are pretty busy during sex. They engorge with increased blood flow, glands within the walls release arousal fluid, it can lengthen by 200%, and contract and squeeze right before orgasm. With all of this going on, the vaginal canal essentially creates an upward suction. A fun little feature for all involved.  

#5 Men release mood enhancers with their sperm

Semen doesn’t just contain the baby-making swimmers. Seminal fluid also carries with it natural mood enhancers like serotonin, oxytocin, cortisol, prolactin, and the sleep hormone melatonin. 

You could call it nature’s antidepressant. Thanks, fellas. 

#6 Your sense of smell heightens

During sex, you experience a 400% increase in the hormone Prolactin. Among other effects, this hormone can light up the part of the brain that interprets scent and in turn heightens your sense of smell. (Sex smell! Maybe this is why we notice it.) 

#7 Pupils dilate

Pupil dilation is a good indication you’re excited by someone. When your brain gets a surge of oxytocin and dopamine, your pupils widen. In fact, pupil dilation is such a great indication of arousal that researchers are exploring using pupil dilation to quantifiably determine sexual orientation. The “windows to our soul” doesn’t lie.

#8 Sperm hauls ass at 28 MPH??

When you first ejaculate, sperm is reportedly released at a whopping 28 miles per hour. (That’s almost twice as fast as a school zone.)

Once sperm is inside the body, however, sperm only travels at 0.2 meters per hour.

#9 Sex is a natural pain killer

The pain-relieving effects are largely caused by the flood of endorphins you experience during sex. Endorphins may relieve pain and induce euphoria. 

#10 During a prostate orgasm, you may not ejaculate

A prostate orgasm is unique in a few ways. 

But a particularly new experience for a lot of guys is the lack of ejaculation during orgasm. When you orgasm from prostate stimulation alone, you may only experience “dribbles of milky ejaculate” vs. the “28 mph ejaculate” you’re used to. This isn’t to say the orgasm is “weaker”, in fact, some guys argue the exact opposite. 

For those new to this type of orgasm, opt for the very best prostate toys and try the hands-free remote control kind. They could be very beneficial in aiding the process. For some, it could take lengthy stimulation sessions so vibes can help.

#11 Oxytocin causes nipples to become erect 

Nipples may harden during initial arousal, sex, and orgasm. This is due to muscle contractions happening within and underneath the nipple. This contraction is thought to be caused by oxytocin and it may make nipples extremely sensitive to stimulation. 

#12 The body releases a hormone that makes it hard to pee

During sex, the body releases an antidiuretic hormone called vasopressin. This hormone may make it difficult to pee after sex. Go figure. 

#13 Your immune system gets a boost

Having regular sex is shown to increase the amount of immunoglobulin you have in your body. This little guy is a crucial part of your immune defense. 

More sex might mean fewer sick days.

The body is pretty amazing, right? 

A lot of the time, the weird things our bodies do during sex actually condition us to want more of it ––and it’s a pretty efficient system we’ve got going on.